When you think about it all diets are a form of fasting that aims to create a calorie deficit – that is consume less calories that you burn and so force the body to make up the difference from your fat reserves.

Effective dieting of all types involves some type of fasting. It is a matter of how you want to have your fast and hunger pangs – a little all the time by eating small portion sizes and low calorie meals or lot by fasting for two days a week.

The 2-day fasting diet with five days of normal eating and two consecutive days of restricted calories has become a sensation especially in Europe where it has been adopted and promoted by several TV personalities. Many TV chefs are renowned for not advocating healthy foods, despite their claims. However, this diet appears to be an exception.

In the extreme version, the advice is to eat nothing and only drink water for two days. But this is very hard to do, despite the claims that fasting boosts your mental capacity and well being.

The milder version advocates restricting calorie intake on the two fasting days to about one quarter of the normal average calorie intake.

The recommended levels are about 500 Calories for women, 600 Calories for men.

What are the Expected Loss Rates on these Diets?

Previous research has shown that the average person consumes far too many calories. Also the general advice given about the rate of weight loss expected from eating fewer calories on diets are generally far too optimistic and misleading.

One example of this sort of claim made by health authorities is:

"Reducing of food intake by 500 Calories per day (2 MJ per day) will produce a weight loss of 1.1 lb (0·5 kg) per week".

People who have tried the 2-day fasting diet have produced some tips shown below. There are many books on the subject and lots of recipes are spring up.

You will need a set of food weight scales and calorie-counting apps or books or recipes with calorie data, to measure your intake accurately when fasting. It is very easy to exceed the limits with snacks. There are some good articles that list low calorie snacks and foods.

Drink lots of plain water, soda water and various teas you like. many drinks have high sugar contents.

Carbohydrates should be avoided when fasting as they contain too many calories for their density. So skip the rice and potatoes and focus on food with a low calorie density.

Stay realistic and compensate for slip ups.

Low-calorie cooking works best if you work with ingredients that have strong flavors such as zesty lemon juice, fresh tangy herbs and pungent spices,

Expected Weight Loss Rates when Fasting 2 Days per Week with zero and very low calorie intake on fasting days

MEN

WOMEN

Average Calories Consumed per day

3000

2000

No Calories Eaten

Weekly loss eating zero calories for two days

6000 Calories per week

4000 calories per week

Average Daily loss eating zero calories for two days

860 calories per day (average)

570 calories per day (average)

Expected weight loss per week

0.33 kg ; 0.73 lb

0.22 kg ; 0.48 lb

Expected weight loss per year

17.2 kg ; 37.8 lb

11.4 kg ; 37.8 lb

Restricted Calories Eaten

Weeky loss eating 600 men and 500 calories women for two days

4800 calories per week

3000 calories per week

Average Daily loss eating 600 men and 500 calories women for two days

685 calories per day

438 calories per day

Expected weight loss per week

0.24 kg ; 0.53 lb

0.17 kg ; 0.37 lb

Expected weight loss per year

13.7 kg ; 30.1 lb

8.8 kg ; 19.3 lb

Recommended Calorie Consumption Rate for Males and Females or Various Ages and Activity Levels